Apparatus for effecting operation of pressure operated mechanisms



1950 J. K.-DOUGLAS APPARATUS Fox EEFECTING OPERATION OF PRESSURE OPERATED MECHANISMS Filed April 8, I949 s A G D F- s s F- R P M o A ..C

INVENTOR JAMES K. DOUGLAS BY%47%W ATTORN EY Patented Oct. 10, 1950 APPARATUS FOR EFFECTING OPERATION OF PRESSURE OPERATED MECHANISMS James K. Douglas, Shorewood, Wisg assignor to The Oilgear Company, Milwaukee, Wis., a corporation of Wisconsin Application April 8, 1949, Serial No. 86,276

Claims. (01.60 52) This invention relates primarily to apparatus for exercising the recoil mechanisms of artillery but the invention is not limited to such use.

An ordinary type of recoil mechanism for a gun includes a recoil cylinder and a recuperator cylinder, both of which are arranged parallel to the un barrel and are fastened thereto, a floating piston which is fitted in the recuperator cylinder and a recoil piston which is fitted in the recoil cylinder and is fixed to a piston rod which extends through the front end of the cylinder, that is, the end'of the cylinder toward the muzzle of the gun. The outer end of 'the piston rod is fastened to the cradle which supports the gun. The recoil cylinder and the portion of the recuperator cylinder in front of the floating piston are filled with oil and are connected to each other by a suitable passage. The recuperator cylinder at the rear of the floating piston is filled with a compressed gas, such as nitrogen, which urges the floating piston forward and thereby maintains the oil under pressure.

When the gun recoils due to being fired, the two cylinders move with it and the recoil piston, being stationary, forces oil out of the recoil cylinder into the recuperator cylinder and the all forces the floatin cylinder rearward'against the gas which cushions and checks the recoil and then causes the floating piston to move forward and force oil out of the recuperator cylinder and into the recoil cylinder to thereby return the gun to firing position.

The relative movements of the pistons and cylinders keeps the surfaces of the pistons lubricated when the gun is in service but during time of peace a great many guns are placed in storage and, if they were allowed to remain entirely inactive, the lubricating film between the pistons and the walls of the cylinders woulddisappear and the pistons would stick to the walls of the cylinders, thereby seriously damaging the recoil mechanisms.

In order to avoid such' damage, the recoil mechanisms of guns in storage are exercised, that is, relative movement between each piston and its cylinder is effected to thereby re-establish a lubricating film between each piston and the wall of its cylinder, only a short relative move-' ment being necessary to re-establish the film. Some completely assembled guns are placed in storage and other guns are partially disassembled before being placed in storage so that it some" times is desirable to exercise a recoil mechanism as a unit and at other times to exercise the parts individually.

. The type of exerciser currently used includes a reversible pump, a cylinder linefor conveying oil from the pump to oneend of one of the cylinders'of:therrecoil mechanism or to the adjacent ends of both of the cylinders to effect movement of one'or both of the'two pistons,a hydraulic jack for moving the recoil piston in the opposite direction, a jack line for conveying oil from the pumputo.,-the:.jack, a meter for measuring-the amount of: .oil delivered to or; discharged from a cylinder to thereby indicate the distance through which a piston is moved, "and valves and other controls including agplurality of push button be pumped to the recuperator cylinder to move the floating cylinder rearward and thereby further compress the gas in the cylinder and then he should inadvertently close the switch which causes the exerciser to. operate automatically, the gas pressure would force oil out of the cylinder and through the meter at such a high velocity that the meter would be driven so fast and the drop in' pressure across the meter would be so great that the meter would be ruined or seriously damaged. 3 i The present invention has as an object to improve the prior exercisen.

Another object is to prevent the meter of an exerciser from being operated at-such high speed that it might be damaged. Other objects'and advantages'will appear from the following description of the exerciser shown schematically in the accompanyin drawing in ciser are both complicated mechanisms but all parts not necessary to an understanding of-the invention have been omitted from the drawing which is purely schematic.

Theexerciser is adapted to exercise the recoil.

mechanisms of all types of guns and it has been shown connected to a recoil mechanism which includes a'recuperator cylinder I having a floating piston 2 fitted therein, a recoil cylinder 3 having a recoil piston 4 fitted therein and a piston rod 5 which is fixed to piston 4 and extends through the end of cylinder 3 for connection to the front end of the cradle (not shown) of the gun. Floating piston 2 divides cylinder l into a gas chamber 6 and aliquid .chamber 1 wh ch is connected by a passage 8 to cylinder 3 adiacent the front end thereof which is the right end in respect to the drawing. Chamber 1 and cylinder 3 normally are filled with oil and chamber 6 is filled with a compressed gas, such as nitrogen, which maintains pressure upon the oil in cylinder 3 and chamber 1 when the recoil mechanism is in operation.

Movement of the floating and recoil pistons toward the left relatively to the cylinders is effected by pumping oil into the right ends of the cylinders. Movement of the recoil piston toward the right is effected by means of a hydraulic jack which includes a piston 9 fitted in a cylinder I!) and provided Wlthfi piston rod H and which is atached to the recoil cylinder after removal of the plug (not shown) which normally closes the left end of the recoil cylinder.

In order that the exerciser may be employed to exercise the recoil mechanisms of a large variety of guns, the hydraulic jack is attached to the recoil cylinder by means-of an adapter one of which is providedfor each kind and size of recoil mechanism. In some instances, an adapter is fitted over theend of a recoil cylinder and is fastened thereon by suitable clamping means and in other instances .an adapter is threaded into the end of the-recoil cylinder. As shown, an adapter I2 is threaded into the end of cylinder 3 and the jack 9-H isinserted into adapter l2 and is fastened thereto by a bayonet joint [3.

Oil for operating jack 9-II and .for moving pistons 2 and 4 toward the left issupplied by a reversible variable delivery pump l! which is supercharged by gear pump l8. and discharges oil into either a channel L9 or a channel 20. Gear pump I8 draws oil from a reservoir 2| and discharges it into a channel :22 which is connected through two check valves Z3.and 24 to channels !9 and 29 respectively. The arrangement is such that gear pump !3 can deliver oil through one check valve 23 or 24 into the channel [9 or I which is connected to the intake of pump I! and the other check valve 23 or 24 will prevent the oil discharged by pump ll from entering channel 22.

Gear pump I8 has been shown separate from pump I1 and is being provided with a separate relief valve 25 through which-oil pumped by gear pump is in excess of requirements is exhausted but in practice gear pump I8 and relief'valve '25 are incorporated in :pump l-l' which also has incorporated therein suitable relief valves for limiting the pressure of the oil discharged into channels IQ and 20.

The oil delivered to and discharged from cylinder 3 and chamber l passes through a hydraulic motor 26 which drives an indicating and control mechanism 2i and which functionsas a meter to measure the amount of oil passing therethrough to thereby cause the indicating mechanism to indicate the extent of movement of piston 2 and/or the extent of movement of 'piston 4.

Flow of oil to and from the cylinders and the jack is controlled in the first instance by a start and stop valve which includes a valve member 3!! fitted in a valve body 3| having four annular grooves or ports 32, 33, 34 and 35 formed therein. Port 32 has a branch of channel I9 connected thereto and port 33 is connected by a channel 36 to meter 26.

Port 34 has connected thereto a channel 31 which has a shut off valve 38 arranged therein and which is c'onnected' by'j afiexible. channel or jack line'39 to-jaok cylinder 10. Port :35 communicates with a channel 40 which is connected through a shut off valve 4| to one end of a flexible channel or cylinder line 42 to the other end of which is adapted to be connected to cylinder I. Jack line 31 and cylinder line 42 are connected, respectively, through two shut off or bleeder valves- 43 and 44 to two channels 45 and 46 which in practice discharge into reservoir 2! but whichqhave been shown as discharging into two auxiliary reservoirs 2 I and 21 in order to avoid complicating the drawing.

The front end head of cylinder I has extending therethrough a'passage' ll' which contains a filling valve (not shown) and which is closed at its outer end byla plug (not shown)" when the recoil mechanism is in operation. Cylinder line 42 may be connected to cylinder 1 by. removing the plug from passage 4l,"screwing.afcharging valve 48 into the end of passage 41., connecting cylinder line 42 to valve 48 and then opening the filling valve by. turning the knob .49 on valve 48 so that oilcanj fiovw through cylinder.=line 4 2 to and from chamber 1; l J

When the exerciser -=is-in;;operation, -oil dise charged from the'recoilrmechanismithrough cyl+ inder line 42 is directed-either to reservoir 2 I or to the intake of pump ILby avalverwhich is fitted in the bore 560i a valve bodyf51 to control communication between five annular, grooves or ports 58, 59, 60, 61 and62 formed inthe wall of bore 56. Port 58 has channel 20 connected thereto. Port 59 is connected to meter 26 by. a channel 63. Port 60 communicates witha channel 64 which discharges into reservoir 21.: Port 6| has a branch of channel 19, connectedthereto. Port 62 is connected to'gear pump :channel 22 bya channel 65 which also. isconnected to the end of bore 56. v l

Valve 55 is urgedtoward the right: to the position shown in Fig. .l by-gear pumppressure and by a spring 66, and it is adaptedto be shifted toward the left to the position shown in Fig. 2 by oil supplied to port fromupump I! or by a servomotor comprising a piston 61 fitted ina ,cylinder 68 which is formedin or;attached to: valve body 5? and is connected by-a channel EiS to channel 4!]. v

The exerciser mechanism iscarried by a two:- wheeled trailer whichamaybe moved closexto :the recoil mechanism to be -exercised. --=In order ,to simplify the drawingnjack line-39 and cylinder line 42 have been shown as being relatively .short but in practice they rare-long enough to'reach from the trailer to opposite ends ofathe recoil mechanism of the largestguns,

Operation After the exerciser has beenplaced'in position, valves 38, 4|, 43 and 44 are opened anda 'switch is closed to start the exercisen that'is,to'cause pumps l1 and I8 to be driven'an'dto cause valve member 30 to move to'the'positio'n shown in Fig; 3 where it remains aslong -as the=exerciseris in operation. Pump H" is then caused to dis} charge oil first in one direction' a nd then in the other to purge from the's'ystem any air that may be therein after which pump l! is'aiijusted to neutral and valves 4|, 43 and 44 are closed.

Then jack 9-| is connected to the left end of cylinder 3 and cylinder line 42 is connected to the right end of cylinder and knob 49 is rotated to open the filling valve as explained above. Bleeder valve 44 is then opened slightly to permit oil to escape from chamber 1 until the pressure therein and in cylinder 3 is reduced to zero after which valve 44 is closed and valve 4| is opened.

If the recoil cylinder is to be exercised independently of the recuperator cylinder, a "jack switch is closed which causes pump H to deliver oil through channel l9, valve body 3|, channel 31, valve 38 and jack line 39 to cylinder N], thereby causing piston 9 to move piston 4 toward the right and piston 4 to eject oil from cylinder 3 through passage 8, chamber 1, valve 48, line 42, valve 4|, channel 48, valve body 3|, channel 36, meter 26, channel 63, valve body 51 and channel 64 into reservoir 2|.

Meter 26 measures the oil flowing therethrough and it operates control 21 which indicates the distance piston 4 is moved and, when piston 4 has been moved to a desired position, the jack switch is released to permit pump I! to go to zero stroke and stop further movement of piston 4. Control 21 is then adjusted until a first reversing switch is closed but that switch is ineffective unless an automatic switch has been closed.

A cylinder switch is then closed which causes pump ll to deliver oil through channel to port 58 in valve body 51 where it will move valve 55 to the position shown in Fig. 2 and then the oil will flow through valve body 51, channel 63, meter 26, channel 36, valve body 3|, channel 40, valve 4|, line 42, valve 48, chamber 1 and passage 8 into cylinder 3 and cause pistons 4 and 9 to move toward the left and piston 9 to eject oil from cylinder l0 through line 39, valve 38, channel 31, valve body 3| and channel I!) to the intake of pump If the displacement of cylinder I0 is less than the displacement of cylinder 3 as shown, the oil returned to pump will be less than the oil discharged by it and the differential oil will be supplied to pump I! by gear pump l8. If the recoil mechanism is for a small gun so that the displacement of cylinder I0 is greater than the displacement of cylinder 3, more oil will be returned to pump l1 than is discharged by it and the differential oil will be discharged through valve body 51, channels 65 and 22 and relief" valve 25 into reservoir 2|.

The oil flowing through meter 26 causes it to operate control 2'! which indicates the distance piston 4 is moved and, when piston 4 reaches a position just short of the end of its stroke toward the left, the cylinder switch is released to permit pump H to go to zero stroke and stop further movement of piston 4. Control 21 is then adjusted until a second reversing switch is closed but that switch is ineffective unless the automatic switch has been closed.

The automatic switch is then closed to render the reversing switches effective and the second reversing switch will establish a circuit to cause pump I! to discharge into channel l9 and thereby cause jack 9| to move piston 4 toward the right as explained above. When pump starts to deliver oil into channel l9, it will at first draw oil from port 58 which will permit spring 66 to move valve 55 to the position shown in Fig. 1 after which pump I1 is supplied with oil by pump I8.

Piston 4'will move toward the right and-meter I 26 willoperate control 2'! until the first reversing;

switch closes and establishes a circuit to effect reversal of pump I1 and thereby cause piston;4

to move toward the left as explained above untilthe second reversing switch closes and causes piston 4 to again move toward the right. The exerciser will continue to operate automatically until piston 4 has been reciprocated a sufficient number of times to positively establish a filmof oil between its periphery and the wallof cylinder 3 and: then a stop switch is manually operated to stop further operation of the exerciser.

If the recoil mechanism is to be exercised as a unit, the exerciser is at first controlled manually as explained above except that the cylinder switch is not released when piston 4 approaches the end of its stroke toward the left but is-held closed until piston 4 has stalled and enough oil has been pumped into chamber 1 to move piston 2 toward the left to a desired position. y After piston 4 stalls, pump I! must create a high pressure in order to enable the oil to move piston 2 toward the left against thefgas pressure in chamber 6, and this pressure extends from,

channel 40 through channel 69 to cylinder 68 and causes piston 6'! to hold valve in the position shown in Fig. 2.

When piston 2 reaches the desired position, the cylinder switch is released to permit pump H to go to zero stroke and then control 2? is so adjusted that the reversing switch is closed when piston 2 is in that position. I

The automatic switch may then be closed to At the same time, the gas pressure in chamber 6 will cause piston 2 to move toward the right and to expel oil from chamber 1 through passage 41, valve 48, line 42, valve 4|, channel 49, valve body 3|, channel 36, meter 26, channel 63, valve body 51 and channel 20 to the intake of pump i! so that piston 2 can move toward the right only as fast as pump ll draws oil from chamber 1.

When piston 2 reaches the limt of its move-.

ment. toward the right, the gas pressure in cham ber 6 is no longer effective to maintain pressure in the cylinder side of the circuit and, since pump I1 is drawing liquid from that side of the cir cuit, the pressure in port 58 will quickly drop to a value low enough to permit spring 66 to move valve 55 t0 the position shown in Fig. 1 thereby preventing pump ll from continuing to discharge through relief valve 25 so that the oil from pump flows to jack 9|| and causes it to move piston 4 toward the right and the oil ejected from cylinder 3 by piston 4 to flow into reservoir 2| as explained above.

Piston 4 will move toward the right until meter 26 closes the first reversing switch to effect re- Then oil IT. The exerciser will continue to operate in this manner until the pistons have been reciprocated aisufiicient number of times to assure'that there is a lubricating film of oil between the periphery of each piston and the wall of its cylinder and then the exerciser may be stoppedby operating a stop switch.

When pump I1 is reversed in response to piston 2 reaching the end of its movement toward the left, meter 26 is rotating at high speed and the inertia of its rotating parts causes it to overrun for an instant and thereby cause a momentary drop in pressure in channel 63 and port 58. If servomotor 6l68 were not provided,the drop in pressure in port 58 would permit spring '66 to shift valve 55 to the position shown in Fig. 1 and thereby connect channel 63 to drain channel 264 so that the high pressure in chamber 1 could operate meter 26 at a terrific speed and the pressure would drop from maximum at the inlet of meter 26 substantially to zero at the outlet thereof and thereby impose an excessive load on k the meter bearings. Operation of the meter at such a high speed and under such a large pressure difierential would seriously damage the meter and might ruin it. However, servo-motor 61-68 prevents valve 55 from assuming the position shown in Fig. 1 and thereby prevents damage to the meter.

If the recuperator cylinder is to be exercised independently of the recoil cylinder, valve 38 is closed, control 21 is adjusted to effect reversal of pump ll when piston 2 reaches the limit of its movement toward the right during automatic operation of the exerciser, then pump H is caused to deliver oil to chamber 1 until piston 2 has been moved to a desired point, and control 21 is adjusted to effect reversal of pump l'! at that point when the exerciser is adjusted for automatic operation.

The automatic switch may then be closed which will cause pump I? to discharge into channel I9. Since at this time the pressure in chamber I is causing servomotor til-68 to hold valve 55 in the position shown in Fig. 2, pump I? will draw oil from chamber l and will discharge it through relief valve 25 into reservoir 21, as explained above, so that piston 2 can move toward the right only as fast as pump I? draws oil from chamber 7. When piston 2 reaches the limit of its movement toward the right, control 2'! will eifect reversal of pump ill and piston 2 will continue to be reciprocated in this manner until the exerciser is stopped.

After the recoil cylinder has been exercised, jack 9H is removed and the plug replaced in the end of cylinder 3. After the recuperator cylinder has been exercised, oil is pumped into chamber l until piston 2 has been moved toward the left to a predetermined point. Then knob 59 is turned in a direction to permit the filling valve to close, line #32 is disconnected from charging valve 48, valve at is removed and the plug is replaced in the end of passage 41.

While the exerciser has been explained as being employed to exercise a particular recoil mechanism, it is capable of exercising any hydro-pneumatic recoil mechanism currently in use in this country. Also, the invention set forth herein is not limited to an exerciser nor to the specific form shown but it is susceptible of various modifications and adaptations without departing from the scope of the invention which is hereby claimed as follows.

I claim:

1. In a system including a cylinder having a piston fitted therein, means adapted when ef- 8.. fe'c'tive to maintain in said cylinder a pressure which tends to move :said piston in one direction, anda hydraulic jackrorimoving said piston in the opposite :direction, the combination of a reversible p'ump for delivering liquid 'to said .0311- inder or tosaid jack to effect movement of said piston in one direction or the other, a valve for connecting said cylinder to said pump or to exhaust, said valve normally being shiftable to a first position in which it connects said cylinder to-ex haustlin response to said pump delivering liquid in a direction to effect operation of said jack and :being shiftable to -a second position in which it connects said cylinder to said pump in response to said pump delivering liquid. in the opposite direction, and a hydraulic actuator adapted in response to the pressure in said cylinder exceeding a predetermined value to shift said valve to said-second position regardless of the-direction in which said pump delivers liquid.

2. In a system including acylinder having a piston ffitted therein, means adapted when effective 'to maintain in said cylinder a pressure which'tends to=move said piston in one direction, and a hydraulic jack for moving said piston in the opposite direction, the combination of a reversible pump for delivering liquid to said cylinder or to .said'jack to efiect movement of said piston inaone direction orthe other, a valveconnected to said cylinder and to exhaust, a;first channel connecting one side of said pump to :said valve, means including a second channel for connecting the:other side of said pump to said jack, said valve being responsive to said pump delivering liquid intosaid first channel for connecting said cylinder 'to said first channel and normally beingresponsive to said pump delivering liquid into said second channel for connecting said cylinder to exhaust, and hydraulic means responsive to the :pressure insaid cylinder exceeding a predetermined value for adjusting said valveto cause it toconnect said-cylinder to said pump and thereby cause the liquid discharged from said cylinderto'pass through said pump.

3. In a system including a cylinder having a piston fitted therein, means adapted when effective to maintain in said cylinder a pressure which tends to move said piston in one direction, and a hydraulic jack for moving said .piston in the opposite direction, the combination of a reversible pump'for delivering liquid to said cylinder or to said jack to effect movement of said piston in one direction or the other, a valveconnected to saidrcylinder and toexhaust, said valve having a, valve member which is yieldingly urged to a first position in which said cylinder is-connected to exhaust and said valve being so constructed that liquid delivered thereto by said pump will shift saidvalve member to a second position in which said cylinder is connected to said pump, and a hydraulic actuator adapted in response to the pressure in said cylinder'exceeding a predetermined value to shift said valve member to said second position regardless of the direction in which said :pump delivers liquid.

4. In a system including a cylinder having a piston fitted therein, means adapted when effective to maintainin said cylinder a pressure which tends to move said piston in one direction, and a hydraulic jack for moving said piston in the opposite direction, the combination of a reversible pump for delivering liquid to said cylinder or to said jack to effect movement of said piston in one direction or the other, a control valve connectedltoisaid cylinder and to exhaust,

a first channel connecting one side of said pump to said valve, means including a second channel for connecting the other side of said pump to said jack and to said valve, a resistance valve connected to said control valve, said control valve having a valve member which is yieldingly urged to a first position in which said cylinder is connected to exhaust and said control valve being so constructed that liquid delivered thereto through said first channel will shift said member to a second position in which liquid is directed from said first channel to said cylinder to effect movement of said piston and said second channel is connected to said resistance valve so that any liquid discharged from said jack in excess of the requirements of said pump will be discharged through said resistance valve, and a hydraulic actuator adapted in response to the pressure in said cylinder exceeding a predetermined value to shift said valve member to said second position regardless of the direction in which said pump delivers liquid.

5. In a system including a cylinder having a piston fitted therein, means adapted when effective to maintain in said cylinder a pressure which tends to move said piston in one direction, and a hydraulic jack for moving said piston in the opposite direction, the combination of a reversible pump for delivering liquid to said cylinder or to said jack to effect movement of said piston in one direction or the other, a control valve connected to said cylinder and to exhaust, a first channel connecting one side of said pump to said valve, means including a second channel for connecting the other side of said pump to said jack and to said valve, a resistance valve connected to said control valve, said control'valve having a valve member which is yieldingly urged to a first position in which said cylinder is connected to exhaust and said control valve bein so constructed that liquid delivered thereto through said first ehannei will shift said member to a second position in which liquid is {directed from said first channel to said cylinder to efiect movement of said piston and said second channel is connected to said resistance valve so that any liquid discharged from said jack in excess of the requirements of said pump will be discharged through said resistance valve, and a hydraulic actuator adapted in response to the pressure'in said cylinder exceeding a predetermined value to shift said valve member to said second position regardless of the direction in which said pump delivers sistance valve.

JAMES K. DOUGLAS.

No references cited. 

